Validación del método inverso para la determinación del flujo de acceso con termodilución / Validation of the inverse method for the determination of the access flow with thermodilution

Introducción: La termodilución es un método ampliamente usado para la medición del flujo de acceso vascular (QA). Entre las posibilidades de la termodilución, el método inverso (MI) puede ser beneficioso en el tiempo de ejecución, sin repercusión en la eficacia dialítica (Kt). Sin embargo, no es una técnica lo suficientemente estudiada.MétodoEstudio transversal sobre 117 fístulas arteriovenosas. Se realizaron 2 mediciones de QA con el método descrito por el fabricante (MR) y otra con MI. El MI se basa en la obtención del registro de recirculación invertida al iniciar la sesión y una única medición posterior de recirculación con las líneas en posición normal. En el análisis de concordancia se utilizó el método Bland-Altman y el índice kappa de Cohen.ResultadosSe evidenció muy buena concordancia entre MR y MI para QA inferiores a 700ml/min, pero empeora a medida que aumenta el flujo. La variabilidad mediana entre las mediciones con MR (variabilidad intramétodo) fue del 3,4% (−17,13). Este valor no difirió de la variabilidad mediana generada entre MR y MI (variabilidad intermétodo), que fue del 2% (−14,12) (p=0,287). El grado de acuerdo entre ambos para identificar fístulas arteriovenosas susceptibles de intervención fue muy bueno (kappa=0,834). El tiempo empleado utilizando el MI fue significativamente menor (p=0,000), sin evidenciarse variaciones en el Kt de las sesiones de medida (p=0,201).ConclusionesEl MI de termodilución es válido para determinar el flujo del acceso vascular, especialmente en QA inferiores a 700ml/min, con gran ahorro de tiempo, simplificación del procedimiento y sin modificar la eficacia de diálisis. La variabilidad entre la medición por MR y MI es similar a la propia del MR. La concordancia entre métodos a la hora de identificar fístulas arteriovenosas potencialmente patológicas es muy buena. (AU)

Introduction: Thermodilution is a widely used method for measuring vascular access flow (QA). Among the possibilities of thermodilution, the reverse method (RM) can be beneficial in the execution time, without impact on the dialysis efficacy (Kt). However, it is not a sufficiently studied technique.MethodTransversal study of 117 arteriovenous fistulas. Two QA measurements were taken with the method described by the manufacturer (MR) and another with RM. RM is based on the obtention of an inverted recirculation registry at the beginning of the session and a single subsequent recirculation measurement with the lines in normal position. In the concordance analysis, the Bland-Altman method and Cohen's Kappa index were used.ResultsVery good concordance between MR and RM was evidenced for QA below 700ml/min, but it worsens as flow increases. The median variability between the MR measurements (intra-method variability) was 3.4% (−17.13). This value did not differ from the median variability generated between MR and RM (inter-method variability), which was 2% (−14,12) (P=.287). The degree of agreement between the 2 to identify arteriovenous fistulas susceptible to intervention was very good (Kappa=0.834). The time spent using the RM was significantly shorter (P=.000) without evidence of variations in the Kt of the measurement sessions (P=.201).ConclusionsThe thermodilution RM is valid to determine the flow of the vascular access, especially in QA lower than 700ml/min, with great time savings, simplification of the procedure and without modifying the dialysis efficiency. The variability between the measurement by MR and RM is similar to that of MR. The concordance between methods in identifying potentially pathological arteriovenous fistulas is very good. (AU)

Validation of the inverse method for the determination of the access flow with thermodilution. / Validación del método inverso para la determinación del flujo de acceso con termodilución.

INTRODUCTION: Thermodilution is a widely used method for measuring vascular access flow (QA). Among the possibilities of thermodilution, the reverse method (RM) can be beneficial in the execution time, without impact on the dialysis efficacy (Kt). However, it is not a sufficiently studied technique. METHOD: Transversal study of 117 arteriovenous fistulas. Two QA measurements were taken with the method described by the manufacturer (MR) and another with RM. RM is based on the obtention of an inverted recirculation registry at the beginning of the session and a single subsequent recirculation measurement with the lines in normal position. In the concordance analysis, the Bland-Altman method and Cohen's Kappa index were used. RESULTS: Very good concordance between MR and RM was evidenced for QA below 700ml/min, but it worsens as flow increases. The median variability between the MR measurements (intra-method variability) was 3.4% (-17.13). This value did not differ from the median variability generated between MR and RM (inter-method variability), which was 2% (-14,12) (P=.287). The degree of agreement between the 2 to identify arteriovenous fistulas susceptible to intervention was very good (Kappa=0.834). The time spent using the RM was significantly shorter (P=.000) without evidence of variations in the Kt of the measurement sessions (P=.201). CONCLUSIONS: The thermodilution RM is valid to determine the flow of the vascular access, especially in QA lower than 700ml/min, with great time savings, simplification of the procedure and without modifying the dialysis efficiency. The variability between the measurement by MR and RM is similar to that of MR. The concordance between methods in identifying potentially pathological arteriovenous fistulas is very good.

Variabilidad intramétodo en medidas del flujo del acceso vascular con termodilución: ¿Un enemigo en los programas de seguimiento? / Intra-method variability in the measurements of vascular access using the thermodilution technique: an enemy in follow-up programs?

OBJETIVO: Analizar el impacto de la variabilidad intramétodo de la Termodilución (TD) en las medidas prospectivas de flujo de acceso (QA) y su relación con los parámetros de seguimiento de primera generación. MÉTODO: Estudio prospectivo. Se realizaron 2 mediciones consecutivas de QA (M1 y M2) y un seguimiento (M3) en 6 meses. Se recogieron datos demográficos y parámetros de seguimiento de primera generación. RESULTADO: Se analizaron 112 fistulas arteriovenosas (-FAV). La mediana de la variabilidad generada entre M1 y M2 no difiere del porcentaje de variación de QA a los 6 meses (p = 0,123). En el 16,8% (14) de los pacientes el QA ha disminuido más del 25% y en un 28,9% (24) aumentó más del 25%. Se evidenció una ligera tendencia a aumentar el porcentaje de descenso de QAa medida que el flujo de las fístulas es mayor (r=-0,229; p = 0,006). Por otra parte, un descenso de QA superior al 25% no se asoció a menor dosis de diálisis (p = 0,183), ni ha aumento significativo de la presión venosa dinámica (p = 0,823) ni al aumento de incidencias durante la punción (p = 0,823). CONCLUSIONES: La presencia de pacientes con aumento de flujo superior a la variabilidad intramétodo y la no asociación entre un descenso superior al 25% y cambios en otros parámetros de seguimiento, hace sospechar la presencia de errores de medición de QA. Frente a ello es conveniente el uso combinado con métodos de primera generación, tanto para establecer el QA basal como para interpretar los descensos en el seguimiento

OBJECTIVE: To analyze the impact of the intra-method variability of thermodilution (TD) in the prospective measurements of the access flow (QA) and the relationship with the first-generation monitoring parameters. METHOD: Prospective study. Two consecutive QAmeasurements (M1 and M2) and a 6-month follow-up (M3) were performed. Demographic data and first-generation follow-up parameters were collected. RESULT: 112 arteriovenous fistulas (AVF) were analyzed. The median variability generated between M1 and M2 does not differ from the percentage of QAvariation at 6 months (p = 0.123). In 16.8% (14) of the patients the QA has decreased by more than 25% and in 28.9% (24) it increased by more than 25%. A slight tendency to increase the percentage of decrease in QA when the fistula flow was higher was evidenced (r=-0.229; p = 0.006). On the other hand, a decrease in QA greater than 25% was not associated with a lower dose of dialysis (p = 0.183), nor did it have a significant increase in dynamic venous pressure (p = 0.823) or an increase in incidences during puncture (p = 0.823). CONCLUSIONS: The presence of patients with an increase in flow greater than the intra-method variability, and the non-association between a decrease greater than 25% and changes in other follow-up parameters, raises suspicions about the presence of QA measurement errors. In relation to this, the combined use with first-generation methods is convenient, both to establish the baseline QA and to interpret the decreases in follow-up

La oxigenoterapia de alto flujo sí tiene un papel en el tratamiento de la bronquiolitis en las plantas de pediatría / High-flow oxygen therapy does have a role in the treatment of bronchiolitis on the paediatric wards

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Influencia del estado nutricional en la evolución clínica del niño hospitalizado / Influence of nutritional status on clinical outcomes in hospitalised children

Introducción: La desnutrición en el paciente pediátrico hospitalizado es una comorbilidad prevalente que puede influir en la evolución clínica y se estima en un 31,4% en nuestro medio. Objetivo: Nuestro objetivo fue describir el riesgo de desnutrición de los pacientes que ingresan en nuestro centro, mediante la herramienta Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), así como analizar su asociación con la evolución del ingreso hospitalario. Métodos: Se realizó un estudio prospectivo, unicéntrico y analítico desde octubre hasta diciembre de 2017 en pacientes hospitalizados, de edades entre 1 mes y 15 años. Se recogieron variables clínicas y datos antropométricos (peso, talla, peso según Waterlow al ingreso (T0), a las 48 h (T1) y al alta (T2). Se construyeron modelos multivariantes para identificar variables predictoras de gravedad. Resultados: Analizamos a 200 pacientes (55% varones) con una mediana de edad de 15,8 meses (RIQ 2,5-42,8) y una estancia media de 3 días (RIQ 1-18 días). El 48,3% presentaba alto riesgo de desnutrición en T0 (STAMP ≥ 4) y un 48,2% riesgo moderado (STAMP = 2-3). En el análisis bivariante, una mayor puntuación de STAMP se asoció a mayor estancia media (p < 0,01) y a mayor gravedad (p < 0,01). En el análisis multivariante, el STAMP en T0 fue predictor de gravedad (OR 1,48; IC 95%: 1,18-1,86; p < 0,01). Conclusiones: Casi el 50% de los pacientes ingresados tenían un elevado riesgo de desnutrición durante el ingreso. El riesgo de desnutrición al ingreso medido según el cribado nutricional STAMP se asoció con una mayor estancia media y mayor gravedad. Es importante evaluar el riesgo de desnutrición al ingreso dada su influencia en la evolución de la enfermedad

Introduction: Paediatric malnutrition during hospital admission is a prevalent comorbidity, which it is estimated around 31.4% in our environment, and could influence the clinical outcomes of paediatric patients. Objective: The aim of this study was to describe the malnutrition risk in hospitalised children using STAMP (Screening Tool for the Assessment of Malnutrition in Paediatrics), and to study its relationship with clinical outcomes. Methods: A single-centre, analytical and prospective study was conducted on children aged 1 month to 15 years hospitalised in a tertiary hospital between October and December 2017. An analysis was made of the clinical data and anthropometric measurements (weight, height, Waterlow weight classification). Patients were classified according to STAMP, which is a validated screening tool used to classify the risk of paediatric malnutrition during hospital admission. Multivariate statistical analysis was used to identify predictive variables of illness severity. Results: An analysis was made on a total of 200 patients (55% male), with a median age of 15.8 months (IQR 2.5-42.8), and a median length of stay of 3 days (IQR 1-18 days). Almost half (48.3%) of them had high risk of malnutrition at admission (STAMP ≥ 4), and 48.2% showed medium risk (STAMP 2-3). A higher STAMP score was associated with longer length of hospital stay (P < .01) and greater severity (P < .01). Multivariable analysis showed that STAMP could be a predictor of illness severity (OR 1.48, 95% CI: 1.18-1.86, P < .01). Conclusions: Nearly 50% of hospitalised children have a high risk of malnutrition at admission according to the STAMP screening tool. Risk of malnutrition at admission measured according to STAMP nutritional screening was associated with a longer length of stay and greater severity of illness. It is important to evaluate the risk of malnutrition as this could be related to illness severity

[Influence of nutritional status on clinical outcomes in hospitalised children]. / Influencia del estado nutricional en la evolución clínica del niño hospitalizado.

INTRODUCTION: Paediatric malnutrition during hospital admission is a prevalent comorbidity, which it is estimated around 31.4% in our environment, and could influence the clinical outcomes of paediatric patients. OBJECTIVE: The aim of this study was to describe the malnutrition risk in hospitalised children using STAMP (Screening Tool for the Assessment of Malnutrition in Paediatrics), and to study its relationship with clinical outcomes. METHODS: A single-centre, analytical and prospective study was conducted on children aged 1 month to 15 years hospitalised in a tertiary hospital between October and December 2017. An analysis was made of the clinical data and anthropometric measurements (weight, height, Waterlow weight classification). Patients were classified according to STAMP, which is a validated screening tool used to classify the risk of paediatric malnutrition during hospital admission. Multivariate statistical analysis was used to identify predictive variables of illness severity. RESULTS: An analysis was made on a total of 200 patients (55% male), with a median age of 15.8 months (IQR 2.5-42.8), and a median length of stay of 3 days (IQR 1-18 days). Almost half (48.3%) of them had high risk of malnutrition at admission (STAMP ≥4), and 48.2% showed medium risk (STAMP 2-3). A higher STAMP score was associated with longer length of hospital stay (P<.01) and greater severity (P<.01). Multivariable analysis showed that STAMP could be a predictor of illness severity (OR 1.48, 95% CI: 1.18-1.86, P<.01). CONCLUSIONS: Nearly 50% of hospitalised children have a high risk of malnutrition at admission according to the STAMP screening tool. Risk of malnutrition at admission measured according to STAMP nutritional screening was associated with a longer length of stay and greater severity of illness. It is important to evaluate the risk of malnutrition as this could be related to illness severity.

Silver nanoparticle based antibacterial methacrylate hydrogels potential for bone graft applications.

Infections are frequent and very undesired occurrences after orthopedic procedures; furthermore, the growing concern caused by the rise in antibiotic resistance is progressively dwindling the efficacy of such drugs. Artificial bone graft materials could solve some of the problems associated with the gold standard use of natural bone graft such as limited bone material, pain at the donor site and rejections if donor tissue is used. We have previously described new acrylate base nanocomposite hydrogels as bone graft materials. In the present paper, we describe the integration of silver nanoparticles in the polymeric mineralized biomaterial to provide non-antibiotic antibacterial activity against Staphylococcus epidermidis and Methicillin-resistant Staphylococcus aureus. Two different crosslinking degrees were tested and the silver nanoparticles were integrated into the composite matrix by means of three different methods: entrapment in the polymeric hydrogel before the mineralization; diffusion during the process of calcium phosphate crystallization and adsorption post-mineralization. The latter being generally the most effective method of encapsulation; however, the adsorption of silver nanoparticles inside the pores of the biomaterial led to a decreasing antibacterial activity for adsorption time longer than 2 days.

Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction-diffusion method.

The present paper describes the synthesis and characterization of a new polymeric biomaterial mineralized with calcium phosphate using the reaction-diffusion method. The scaffold of this biomaterial was a hydrogel constituted by biocompatible polyethylene glycol methyl ether methacrylate (PEGMEM) and 2-(dimethylamino)ethyl methacrylate (DMAEM), which were cross-linked with N-N'-methylenebisacrylamide (BIS). The cross-linking content of the hydrogels was varied from 0.25% to 15% (w/w). The gels were used as matrix where two reactants (Na2HPO4 and CaCl2) diffused from both ends of the gel and upon encountering produced calcium phosphate crystals that precipitated within the polymer matrix forming bands. The shape of the crystals was tuned by modifying the matrix porosity in such a way that when the polymer matrix was slightly reticulated the diffusion reaction produced round calcium phosphate microcrystals, whilst when the polymer matrix was highly reticulated the reaction yielded flat calcium phosphate crystals. Selected area electron diffraction performed on the nanocrystals that constitute the microcrystals showed that they were formed by Brushite (CaHPO4.2H2O). This new composite material could be useful in medical and dentistry applications such as bone regeneration, bone repair or tissue engineering.

Biocatalytic oxidation of phenolic compounds by bovine methemoglobin in the presence of H2O2: quantitative structure-activity relationships.

In the present work, 13 p-substituted phenols with different functional groups have been systematically evaluated as metHb substrates by means of HPLC analysis. Non-hyperbolic kinetics were observed and Hill coefficients in the 0.37-1.00 range were obtained. The catalytic constants and the Hill coefficients were found to be quantitatively correlated with two independent variables: the energy level of the highest-occupied molecular orbital (E(HOMO)), which describes the intrinsic redox activity of the substrates and the pK(a)-values, which are related to substrate ionization. Oxygen evolution in the presence of each phenol derivative was also measured, and good correlation between peroxidase-like and catalase-like activities of the protein was observed. It is also shown that bovine metHb, although less active than other peroxidases, may represent a good alternative from an economical point of view for phenol removal processes. The equations here obtained may serve as a basis to further explore the potential use of metHb-mediated reactions in the treatment of phenols in wastewaters and to predict which phenol will be removed most efficiently under this treatment with satisfactory reliability.

Síndrome de reconstitución inmunitaria secundario a hepatitis C en una niña infectada por el VIH / Immune restoration syndrome secondary to hepatitis C virus infection in an HIV-infected pediatric patient

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